package com.vanvalt.payhui.util.encrypt;

import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

/**
 * Copyright 2007 GuangZhou Cotel Co. Ltd. All right reserved. DES加密解密类.
 * 
 * @author <a href="mailto:xiexingxing1121@126.com"
 *         mce_href="mailto:xiexingxing1121@126.com">AmigoXie</a>
 * @version 1.0 Creation date: 2007-7-31 - 上午11:59:28
 */
public class DESUtils {
	/** 加密、解密key. */
	private static final String	PASSWORD_CRYPT_KEY	= "kEHrDooxWHCWtfeSxvDvgqZq";
	/** 加密算法,可用 DES,DESede,Blowfish. */
	private final static String	ALGORITHM			= "DES";

	public static void main(String[] args) throws Exception {
		String md5Password = "111111";
		String str = DESUtils.encrypt(md5Password);
		System.out.println("str: " + str);
		str = DESUtils.decrypt(str);
		System.out.println("str: " + str);
	}

	/**
	 * 对数据进行DES加密.
	 * 
	 * @param data
	 *            待进行DES加密的数据
	 * @return 返回经过DES加密后的数据
	 * @throws Exception
	 * @author <a href="mailto:xiexingxing1121@126.com"
	 *         mce_href="mailto:xiexingxing1121@126.com">AmigoXie</a> Creation
	 *         date: 2007-7-31 - 下午12:06:24
	 */
	public final static String decrypt(String data) throws Exception {
		if (data.length() % 8 != 0) return data;
		return new String(decrypt(hex2byte(data.getBytes()), PASSWORD_CRYPT_KEY.getBytes()));
	}

	/**
	 * 对用DES加密过的数据进行解密.
	 * 
	 * @param data
	 *            DES加密数据
	 * @return 返回解密后的数据
	 * @throws Exception
	 * @author <a href="mailto:xiexingxing1121@126.com"
	 *         mce_href="mailto:xiexingxing1121@126.com">AmigoXie</a> Creation
	 *         date: 2007-7-31 - 下午12:07:54
	 */
	public final static String encrypt(String data) throws Exception {
		System.out.println("加密后："+encrypt(data.getBytes(), PASSWORD_CRYPT_KEY.getBytes()));
		return byte2hex(encrypt(data.getBytes(), PASSWORD_CRYPT_KEY.getBytes()));
	}

	/**
	 * 用指定的key对数据进行DES加密.
	 * 
	 * @param data
	 *            待加密的数据
	 * @param key
	 *            DES加密的key
	 * @return 返回DES加密后的数据
	 * @throws Exception
	 * @author <a href="mailto:xiexingxing1121@126.com"
	 *         mce_href="mailto:xiexingxing1121@126.com">AmigoXie</a> Creation
	 *         date: 2007-7-31 - 下午12:09:03
	 */
	private static byte[] encrypt(byte[] data, byte[] key) throws Exception {
		// DES算法要求有一个可信任的随机数源
		SecureRandom sr = new SecureRandom();
		// 从原始密匙数据创建DESKeySpec对象
		DESKeySpec dks = new DESKeySpec(key);
		// 创建一个密匙工厂，然后用它把DESKeySpec转换成
		// 一个SecretKey对象
		SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(ALGORITHM);
		SecretKey securekey = keyFactory.generateSecret(dks);
		// Cipher对象实际完成加密操作
		Cipher cipher = Cipher.getInstance(ALGORITHM);
		// 用密匙初始化Cipher对象
		cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);
		// 现在，获取数据并加密
		// 正式执行加密操作
		return cipher.doFinal(data);
	}

	/**
	 * 用指定的key对数据进行DES解密.
	 * 
	 * @param data
	 *            待解密的数据
	 * @param key
	 *            DES解密的key
	 * @return 返回DES解密后的数据
	 * @throws Exception
	 * @author <a href="mailto:xiexingxing1121@126.com"
	 *         mce_href="mailto:xiexingxing1121@126.com">AmigoXie</a> Creation
	 *         date: 2007-7-31 - 下午12:10:34
	 */
	private static byte[] decrypt(byte[] data, byte[] key) throws Exception {
		// DES算法要求有一个可信任的随机数源
		SecureRandom sr = new SecureRandom();
		// 从原始密匙数据创建一个DESKeySpec对象
		DESKeySpec dks = new DESKeySpec(key);
		// 创建一个密匙工厂，然后用它把DESKeySpec对象转换成
		// 一个SecretKey对象
		SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(ALGORITHM);
		SecretKey securekey = keyFactory.generateSecret(dks);
		// Cipher对象实际完成解密操作
		Cipher cipher = Cipher.getInstance(ALGORITHM);
		// 用密匙初始化Cipher对象
		cipher.init(Cipher.DECRYPT_MODE, securekey, sr);
		// 现在，获取数据并解密
		// 正式执行解密操作
		return cipher.doFinal(data);
	}

	public static byte[] hex2byte(byte[] b) {
		if ((b.length % 2) != 0) throw new IllegalArgumentException("长度不是偶数");
		byte[] b2 = new byte[b.length / 2];
		for (int n = 0; n < b.length; n += 2) {
			String item = new String(b, n, 2);
			b2[n / 2] = (byte) Integer.parseInt(item, 16);
		}
		return b2;
	}

	public static String byte2hex(byte[] b) {
		String hs = "";
		String stmp = "";
		for (int n = 0; n < b.length; n++) {
			stmp = (java.lang.Integer.toHexString(b[n] & 0XFF));
			if (stmp.length() == 1)
				hs = hs + "0" + stmp;
			else
				hs = hs + stmp;
		}
		return hs.toUpperCase();
	}
}